Feedback option in proc sql statement we use to display columns in logs. so what is use of it?There is any benefit to see columns in log files.
It's one of a number of tools that can be useful in debugging and tracing data lineage. It doesn't just display columns - it also expands any VIEWS to help further with understanding the underlying execution operations. For regular, stable, production jobs - it's probably not helpful.
For debugging that one job, that was written 15 years ago by somebody who has now disappeared - priceless.
There's a great paper on it here: http://analytics.ncsu.edu/sesug/2012/CT-05.pdf
Yes, it's helpful for the lazy programmer like me.
I often use FEEDBACK to expand the * list out to a full set of variables with the appropriate alias and then manually select out the variables I want. So I use it as a code generation tool. You won't see it in PROD code because I only use it for development, but that's just a single example.
proc sql feedback;
create table want as
select * , '1' as union_join
from sashelp.class
union
select * , '2' as union_join
from sashelp.air;
quit;
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